1. Technical Field
The present invention relates to an information processing apparatus, and relates in particular to an information processing apparatus that can improve the use of contents managed based on licensing information.
2. Description of Related Art
As digital technology has been developed, digital contents, such as ringtone melodies for mobile phones and games for mobile phones, can be provided for mobile phones and information processing apparatuses through a network, such as the Internet.
Unlike analog contents, the quality of digital contents is not deteriorated through the repetitive copying of the contents. Once digital contents are distributed on the market, the contents can be copied by an unauthorized party to a mobile phone, or to an information processing apparatus, without permission of the copyright holder of the contents.
Therefore, for the sale of digital contents to users, content providers supply licensing information for the users that authorizes them to use the contents, and this tends to reduce the possibility that the contents will be used by unauthorized users who have not obtained licensing information (i.e., users who do not purchase contents through the proper channels). The contents for which licensing information is provided at the time of purchase are defined as “contents managed based on licensing information”.
Recently, of the contents on the market that are managed using licensing, there are some that users can secure for unlimited, monthly using by paying several hundred yen each month, and some (hereinafter referred to as “use limited contents”), for which use is made of copyright protected file forms (OMA Separate Delivery forms), such as those used for display wallpapers for information processing apparatuses or for ringtone melodies used for mobile phones, for which limitations are imposed in advance on usage periods or on usage frequency factors, that are based on licensing information. Unlike use limited contents for which usage periods are limited, use limited contents for which the number of times used is limited in advance can not be designated for use for display wallpapers or for ringtones.
When for contents a predesignated limited usage period has expired or a limited number of times allocated for use of the contents has been reached, the use of the contents is thereafter inhibited, and a user can no longer use (reproduce or display) the contents.
However, assume that there is a difference between the timer incorporated in a user's mobile phone or information processing apparatus and the timer in a contents server operated by a contents provider. In this case, although the use period for the use limited contents was previously established, as stipulated using licensing information, the use of the contents can not be inhibited exactly at the time designated for the expiration of the use period.
Therefore, a method has been proposed whereby a use time period and time differential information for the internal clock are provided in advance as contents information, and the contents information is transmitted to a client apparatus (see, for example, JP-A-2001-265662).
According to the method disclosed in JP-A-2001-265662, upon the distribution of contents, a contents provider and a user conclude an agreement on the use period, and when a time difference occurs in the clock of a device following the distribution of the contents, the elapsed time for the use period can be determined exactly. Therefore, when the use limit that the contents provider desires is reached, the use of the contents can be accurately inhibited.